Carrier Bat (伝書バット,Densho Batto?) is a message delivery animal of the World Government to the pirates. Its name is a pun on carrier pigeon (伝書鳩,Densho Bato?). So far in the series, two carrier bats have appeared; one shown in Jinbe's flashback delivering a message to Jinbe inviting him to become a Shichibukai, and the other appearing before the timeskip delivering a message to Buggy whose contents are now know to have also been an invitation to join the Shichibukai. It first appeared in Chapter 593 and Episode 512.[3]

Very common snakes found around the island and used as weapons by the Kuja. There seems to be many different variations as small and large snakes have been seen and slightly differ in looks, but all have a large smile. They are trained to be used as bows for the Amazons. They debuted in Chapter 514 and Episode 408.[4]

Yuda (遊蛇（ユダ）,Yuda?, literally meaning "Traveling Snake") are a ferocious and poisonous type of sea serpent. They live in the Calm Belt and are so dangerous that they are one of the few creatures that Sea Kings will not attack, though the Kuja people apparently were able to domesticate them. Boa Hancock and her two sisters own a ship which is drawn by these creatures, a newly added method of navigating through the Calm Belt.[5] They resemble Snake Weapons but are much larger and have hair on their head that also runs along their backs and around their necks, as well as having slit eyes while snake weapons have dotted eyes. They first debuted in Chapter 516 and Episode 409.[5]

A Blue Gorilla (ブルーゴリラ,Burū Gorira?), nicknamed Blugori (ブルゴリ,Burugori?) by the Impel Down guards and prisoners, is a large masked gorilla-like beast with a skull painted on where its face should be. Blue Gorillas wield double-sided battle-axes and have incredible physical prowess, to the point of hunting Sea Kings for food.[9] However, they are mindless creatures and are under the command of Saldeath, who controls them with a flute.[10] They first appeared in Chapter 526 and Episode 423.[9]

In the manga, they have blue cloaks with dark blue fur, the black skull mark on the face is white on the "skull nose" and yellow on the eyes, and appear to have yellow flat somewhat cubed hands and feet, as obvious to their namesakes. In the anime opening, they have white cloaks with black fur on the lower half, brown fur on the wrists, and the skull mark on the face was colored a light black while the "skull nose" and eyes were red. This error was eventually fixed in their first official appearance.

The Puzzle Scorpions (パズルサソリ,Pazuru Sasori?) are scorpions found in Level 2: Beast Hell of Impel Down. The Puzzle Scorpions look like large, cartoon scorpions. When they fuse together, they look like giant centipedes. In the anime, it first appeared as a big red scorpion. When Luffy and his company struck the animal, it immediately broke into pieces, in which it appears that the big scorpion is actually composed of smaller version scorpions. The Puzzle Scorpions are extremely poisonous. They first appeared in Chapter 529 and Episode 430.[11]

The Puzzle Scorpions first appeared in Level 2, giving Luffy, Buggy, and Mr. 3 trouble when they tried to reach to the lower levels to rescue Portgas D. Ace. When Luffy led a mass-breakout army, the Puzzle Scorpions were once again trying to impede their moves, but ultimately failed.

The Manticores (マンティコラ,Mantikora?) are man-eating animals found in Level 2: Beast Hell of Impel Down. The Manticore are animals with human faces, but lion bodies, being based on the legendary creatures of the same name. Each of their faces are different, similar to actual humans. They are able to imitate human speech because their face is human-like. They are only imitating what they have heard the prisoners say and they do not know what those words mean. They may refer to panties or food.[12]

The Basilisk (バシリスク,Bashirisuku?) is the second-in-command of Impel Down's Level 2: Beast Hell, under the Sphinx. The Basilisk is a gigantic chicken like creature, with its tongue sticking out in a deranged manner, and is said to be the offspring of a chicken and snake. It first appeared in Chapter 528 and Episode 425.[14] While named after the basilisk, it looks more like the cockatrice; these two creatures are often confused with each other and are sometimes synonymous.

A giant Sphinx (スフィンクス,Sufinkusu?) is the boss of Impel Down's Level 2: Beast Hell. The Sphinx is a gigantic creature with a dark humanoid face and a winged, leonine body. Similar to the Manticores that it leads, the Sphinx mimics words that it hears from the people around it, but does not understand what those words mean. He usually refers to different types of noodles. It first appeared in Chapter 529 and Episode 430.[15] It is based on the famous mythological creature.

Multiple sphinx appear on Whitebeard's home island and many of them are used as domestic animals from people, like Tama.[16]

The Wolf Unit (軍隊ウルフ,Guntai Urufu?, "Army Wolves" in the English versions) are a pack of vicious wolves stationed in Impel Down's Level 5: Freezing Hell. The wolves look like typical wolves, except their strange looking eyes make them look deranged and insane, and they tend to stick out their tongues, which further increases their bloodthirsty appearances. The wolves are powerful enough to overwhelm even the top savage animals of Level 2. As such, they are reassigned to guard Level 5 criminals. The wolves also seem to be resistant to the bitter cold of Level 5. They may be the result of genetic modifications, as a wolf appears in the background when the Bloodline Elements and their modifications are being described in Chapter 840.[17] Their first appearance is in Chapter 536 and Episode 425.[18]

A humandrill (ヒューマンドリル,Hyūmandoriru?) is a type of mandrill that Roronoa Zoro encountered in Kuraigana Island. They are highly intelligent creatures capable of imitating humans so much that they will mimic any trait they witness. One of the humandrills even used spit to try to heal its wounds, which is a folklore remedy. If they were to see peace they would become pacifistic creatures; however, nine years ago, they witnessed a war on Kuraigana Island, causing them to learn how to wield weapons and become bloodthirsty warriors.[22] As stated by Mihawk himself, the only reason why humans are dominant over beasts, despite the latter's physiological advantages over the former, is because people have the capacity to learn and improve. With these advantages in the possession of beasts, they become more dominant.

The Humandrills are extremely powerful due to their beastly physical prowess which greatly supplement their self taught fighting skills. They were a major obstacle to Zoro when he tried to reach the ocean and they even destroyed the boat that Dracule Mihawk gave him to leave the island. One of them was seen withstanding Zoro's Oni Giri attack without falling to the ground, using spit to heal its wound. Perhaps a great testimony to their fighting strength would be when Mihawk reacted with visible surprise after Zoro revealed that he had defeated them all.[23]. This implies that even the Shichibukai acknowledges their strength. Nevertheless, they are afraid of the Shichibukai[24] to the point that they do not even dare to come near his castle.[25]

In the anime, the Humandrills' behavior has been explained greater than in the manga. They were able to imitate Zoro's santoryu techniques just by seeing them. When Zoro defeated them, Mihawk explained to him that he defeated only a part of them and that by imitating the soldier of the war on Kuraigana Island they even imitated their ranks system, thus meaning that mandrills organized themselves like a real army. Finally, the most incredible test of their high intelligence is that one of them managed to imitate Mihawk's swordsmanship, even developing a white copy of his sword, the Kokutou Yoru; thus becoming the leader of the Humandrills army.

Their name is a combination of the word "human" (which they imitate) and mandrills, the type of monkey which they resemble.

The Big Tiger (大虎,Ōtora?) is seen in the forest of Goa Kingdom. It is a very fierce and big tiger that tries to eat young Luffy in the manga and also takes Luffy's "first hunting prize" in the anime. 12 years ago from the current storyline, Luffy, Ace, and Sabo were no match to the tiger, even if they fought together. It seems to be able to handle cold climates since it appears in a snowy mountain before Luffy and the others. The Big Tiger has the ability to attack with its tail, as shown in the anime. Later on, Luffy, Ace, and Sabo defeat the tiger together after training with Naguri. It first appeared in Chapter 583 and Episode 498.[26]

A Wild Bear appears several times in the flashback of Luffy in Goa Kingdom. In the anime, its strength, as stated by young Ace, is about the same as the Large Tiger, and it could not be defeated by young Ace, Luffy, and Sabo until Naguri came and forced it back to the forest using Haki. It first appeared in Chapter 589 and Episode 498.[27]

The Domo Penguin (ドウモウペンギン,Dōmō Pengin?, "Fierce Penguin") is a type of penguin that is native to Hyokaido. It generally resembles a blue Rockhopper Penguin with a Puffin like beak. Large groups of this penguin are able to move the various icebergs in Hyokaido from underneath. The Accino Family use these penguins' ability to move icebergs to trap their prey's ship between the various icebergs in Hyokaido.

A Domo Penguin.

A Domo Penguin's height compared to a normal human, Sanji.

The penguins themselves are very vicious. Large groups of them can cause trouble for anyone in their way. The Accino Family thus also use the penguins' vicious nature against their prey. It only appeared in the anime in Episode 329.[28]

The hippo found in Level 2: Beast Hell of Impel Down can expand its mouth making it big enough to eat Buggy's body and is really fast but is unable to turn while running. It is unknown if its mouth enlarging ability is a Devil Fruit power similar to Wapol or a natural ability. It first appeared in the anime in Episode 425.

The Monster Mantis is a praying mantis with scythes and a uniform. It can fly and slice very quickly. It can be found in Level 2: Beast Hell of Impel Down. Dressed up like a jailer, the mantis attacked Luffy and Buggy showing a great skill with its blades. Unluckily, after an attack, it got stuck in the pavement, just before being blown away by a roar of the Basilisk. It first appeared in Episode 425.[29]

The danpa (ダンパ,Danpa?) is shown to be Luffy's "first hunting prize" in the anime (Episode 498) in Goa Kingdom. Its name is a pun on pandas, and its fur patterns are opposite from a panda's as well; dark where pandas would be white and white where pandas would be dark colored. It is not very strong compared to the Large Tiger since young Luffy "caught" it very easily. Danpas probably do not hibernate, since it is seen running away from Luffy and the trio in a snowy mountain. It only appeared in Episode 498.[30]